Related Party Transactions - Schedule of Expenses Incurred (Details) - Dow - USD ($) $ in Thousands	5 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Payment amount for services	$ 8,731	$ 5,138	$ 8,361
Amortization of prepayment related to set-up of transition services
Related Party Transaction [Line Items]
Payment amount for services	2,647	827	1,526
Ongoing costs of the transition services agreement / Rent and Other
Related Party Transaction [Line Items]
Payment amount for services	4,531	2,970	4,346
Amortization of prepayment related to Dow importation services
Related Party Transaction [Line Items]
Payment amount for services	220	0	397
Rent expense | Ongoing costs of the transition services agreement / Rent and Other
Related Party Transaction [Line Items]
Payment amount for services	740	902	1,198
Other expense | Ongoing costs of the transition services agreement / Rent and Other
Related Party Transaction [Line Items]
Payment amount for services	$ 593	$ 439	$ 894